# The Lost Book of Undersea Adventure \(The Unknown Adventurer\)

The Lost Book of Undersea Adventure is a 96-page illustrated adventure journal from the Unknown Adventurer series. It follows an island survival story that leads to underwater discovery, presented with handwritten sections, notes and inserted-page styling.

- [Original product page](https://bargainpostbox.co.uk/product/the-lost-book-of-undersea-adventure-unknown-adventurer)
- [View offer](https://bargainpostbox.co.uk/visit/the-lost-book-of-undersea-adventure-unknown-adventurer)
- Market: UK
- Language: en-GB
- Currency: GBP
- Category: Books, Music & Hobbies > Books, Music & Movies > Books & Comics
- Price: 9.00 GBP
- Previous price: 14.99 GBP
- Discount: 40%
- Price checked: 2026-11-13T05:50:20.756Z
- Rating: 4.7 / 5
- Reviews: 50

Prices and deal status are the latest recorded data, not a guarantee of availability. Confirm the price and availability with the store.

## At a glance

- Illustrated story of survival, friendship and undersea discovery.
- Presented in an artist’s journal style with handwritten sections, smudged notes and stuck-in pages.
- The story begins with the Unknown Adventurer stranded on a mysterious island and investigating what lies beyond its lagoon.
- The listing identifies this as another adventure in the Unknown Adventurer series.

## Pros

- Journal-style presentation and detailed illustrations offer more visual variety than a plain-text story.
- The island-survival plot develops into underwater exploration, combining adventure with a marine setting.
- A compact 96-page length may suit younger readers looking for a shorter illustrated book.

## Specifications

### Book details
- Publisher: Frances Lincoln Children's Books
- Publication date: 5 Jun. 2025
- Language: English
- Print length: 96 pages
- ISBN-10: 0711296766
- ISBN-13: 978-0711296763
- Reading age: 6 - 12 years, from customers
- Grade level: 2 - 6
### Dimensions and installation
- Dimensions: 23.5 x 0.51 x 29.01 cm
- Weight listed: 500 g

## Before you buy

- The listed reading age is attributed to customers rather than presented as a publisher-set age recommendation. The description also frames the story as a quest for sea nomads and as an island survival and underwater discovery tale. These appear to be different plot emphases rather than a stated contradiction.

## A good fit for

- Children drawn to illustrated adventure stories, survival plots and underwater settings.
- Readers who enjoy books styled as journals, with handwritten notes and inserted-page details.
- Gift buyers looking for an adventure book listed for ages 6–12.

## Less suited to

- Readers looking specifically for a factual marine-life reference book rather than an adventure story.
- Buyers seeking a long novel, since the listing gives a print length of 96 pages.

## Customer feedback

The listing provides aggregate ratings but no customer-comment summary, so these figures cannot show what readers liked or disliked or why. The distribution is strongly weighted towards five-star ratings, but includes a small share of lower ratings. Treat this as a broad satisfaction signal rather than evidence about the illustrations, story or suitability for a particular child.

## Frequently asked questions

### What is The Lost Book of Undersea Adventure about?
The listing describes the Unknown Adventurer being stranded on a deserted island, testing survival skills and investigating a mystery that leads beneath the waves.
### How is the story presented?
It is described as an artist’s journal, with handwritten sections, smudged notes, stuck-in pages and detailed illustrations.
### What age group is it listed for?
The product details say “6 - 12 years, from customers” and give grade level “2 - 6”. The reading-age wording is customer-attributed, not a stated publisher recommendation.
### How long is the book?
The listing gives a print length of 96 pages.

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## Add-ons

- [The Lost Book of Adventure: from the notebooks of the Unknown Adventurer](https://bargainpostbox.co.uk/visit/the-lost-book-of-undersea-adventure-unknown-adventurer)

## Images

![The Lost Book of Undersea Adventure \(The Unknown Adventurer\) — 1](https://bargainpostbox.co.uk/i/2I8gcDGTkRkYFchU7oh_qfTtXjsnaOep4YlbIy0Jz7rGOpD_wwFYWUUxwMSJ2hPVWC_S-xXbSWKk1Td8QqZxytxKy2KOT4siipNwJ02pR9oESPzn-pLl.jpg)

![The Lost Book of Undersea Adventure \(The Unknown Adventurer\) — 2](https://bargainpostbox.co.uk/i/_ewIGhwbLx0GnhSAk0oLbN9429CJ6ArBCLU1SoV_LkBzDu9BUcnX_Aoc5b-GD10qO4G7d5L8ip1nYCOjKhuFp5y7mYJlC20chUhDuNB24WI-5C6-pqAQ.jpg)

![The Lost Book of Undersea Adventure \(The Unknown Adventurer\) — 3](https://bargainpostbox.co.uk/i/lcyNl4A4ysWX_POxvAZwI0gzTUL8zFI6UNbLWfbFAKt1qRF-yb8015JT_xlPDfYl1mQRozULhYn8dkUFCckg1BsXVdO-hdHFZCXH2t2DaW0GonwnRTBu.jpg)

![The Lost Book of Undersea Adventure \(The Unknown Adventurer\) — 4](https://bargainpostbox.co.uk/i/-Dn1V-TFql750cOwQTn6pJO1QtWbUKWv_B5Q0HYGLyRygWpdQh3U4AbK4fN4MF5ds140oFvjUyhUBRaeguNbyz3qhdwsXnczLnswflUiMlqGloSPWlGe.jpg)

![The Lost Book of Undersea Adventure \(The Unknown Adventurer\) — 5](https://bargainpostbox.co.uk/i/syqzW9r-egkrc7O7Hg8Ml2hdVad4gU9ILn2k-4M0ZQCq9TTMAPY30cSRPtZ_D2m80-TvjNOO9G5OKUEo8oTFrsJrPQXXTgTsSX49CM4j3ikZjRG5FNmw.jpg)

![The Lost Book of Undersea Adventure \(The Unknown Adventurer\) — 6](https://bargainpostbox.co.uk/i/TN-d_ifxMQsM1FQPFp1Y1eRnHFTj44yvbYT5upKaTlzdzgFro3yItY0lC3Jy_ApouadCpsqPXfQghRhF6TWhQRgaxJLXBZRmiUZAzh8qkG4TAhmKitvP.jpg)

![The Lost Book of Undersea Adventure \(The Unknown Adventurer\) — 7](https://bargainpostbox.co.uk/i/8_W6-zOsn79gMQgSTmuatZ10dtRrCN1jaHAzLf6kSfFQlZ1Zp8SuidDCzSxyccSFD7mE0hvoVWDNGOoeJarh8_wdgPTrQzszR2K3vGayXFTMEZJZG5kM.jpg)